1. Technical Field
This invention relates to the assembly and erection of utility poles.
2. Description of the Prior Art
Metal utility poles generally are tubular and may take any general tubular shape but are usually cylindrical or octagonal. They are usually fabricated in sections for efficiency in the fabrication process and ease of transportation. After the sections are fabricated, they are attached one to the other for a longer pole. Some such poles have been attached at the utility pole fabricators and then the assembled poles transported to the utility for erection. However, this has the disadvantage of requiring the shipping of over-length utility poles and of handling very heavy utility poles. Consequently, some utility poles are shipped in sections to the site, assembled and erected. For ease in assembly, the sections of a utility pole are tapered and the upper sections are inserted into the bottom sections with sufficient force so that they do not come apart when being erected since if the bottom section dropped out when the pole is being pulled vertically it could result in injury to the personnel as well as damage. Accordingly, the sections must be pulled together with considerable force under standards that are set by the manufacturer to ensure they will not come apart.
In one technique for pulling the utility pole sections together, hydraulic cylinders are attached on opposite sides of a first section of utility pole and corresponding brackets are attached to a second section that is dimensioned to fit into the first section. The hydraulic cylinders and tug brackets are bolted to the sections of utility pole, using nuts provided by the manufacturer. The first and second sections contain a taper selected by pole fabricator to provide a fit that becomes increasing tight as the sections are pulled together. The manufacturer selects the taper and publishes the relationship between force needed to compress the two sections together and the distance the upper section is telescoped over the lower section. A tug arm connects the piston rods of the hydraulic cylinders with the corresponding brackets. The tug arm is pulled by the hydraulic cylinders to pull the poles together in an assembly operation and pushed by the hydraulic cylinders to disassemble sections.
One prior art type of hydraulic cylinder has a stroke sufficiently large to pull the sections together with sufficient force for fastening. Other prior art hydraulic cylinders have shorter strokes. However, the prior art arrangements utilizing relatively short stroke hydraulic cylinders use a heavy steel ladder-typed member to connect the hydraulic piston on one section to the bracket on the other. The sections are pulled together in increments and between increments, the steel ladders are manually adjusted to a new location on the bracket so that the sections can be pulled another increment.
This prior art arrangement has several disadvantages, such as for example: (1) it is heavy and difficult to move; (2) it requires a time consuming and difficult operation in adjusting the position of the ladder-type bracket; and (3) it is relatively expensive.
Accordingly, it is an object of the invention to provide a novel apparatus and method for erecting metal utility poles.
It is further object of the invention to provide a novel apparatus and method for assembling the sections of a utility pole.
It is a still further object of the invention to provide a novel method of assembling and erecting utility poles that is less expensive and less time consuming than prior art systems.
It is a still further object of the invention to provide economical equipment for assembling sections of a utility pole.
It is still further object of the invention to provide equipment which is relatively light and easier to transport than prior art equipment for assembling the sections of utility poles.
It is a still further object of the invention to provide equipment that cooperates with existing equipment normally at a utility pole erection site to assembly utility poles.